►A roller coaster is one of the most popular amusement rides in amusement parks and theme parks around the world. ►Generally speaking, this ride can employ a form of elevated railroad track designed with tight turns, steep slopes, and sometimes inversions, and people ride along the track in open cars, feeling nervous and excited. The track in a coaster design does not necessarily have to be a complete circuit, as shuttle roller coasters demonstrate. Most roller coasters have multiple cars in which passengers sit and are restrained.